Estimates show hundreds of millions of trees killed by drought

Tuesday

Dec 20, 2011 at 12:01 AMDec 20, 2011 at 4:00 AM

COLLEGE STATION – As many as 500 million trees scattered across the Lone Star State have died this year as a result of the unrelenting drought, according to preliminary estimates from Texas Forest Service.

The numbers were derived by Texas Forest Service foresters, who canvassed local forestry professionals, gathering information from them on the drought and its effect on trees in their respective communities.

Each forestry expert estimated the percentage of trees in their region that have died as a result of the 2011 drought. That percentage was applied to the estimated number of trees in the region, a figure determined by the agency's Forest Inventory & Analysis (FIA) program.

Using this approach, an estimated 100 million to 500 million trees with a diameter of 5 inches or larger were estimated to have succumbed to the drought. That range is equivalent to 2 to 10 percent of the state's 4.9 billion trees.

"In 2011, Texas experienced an exceptional drought, prolonged high winds and record-setting temperatures. Together, those conditions took a severe toll on trees across the state," said Burl Carraway, Sustainable Forestry department head. "Large numbers of trees in both urban communities and rural forests have died or are struggling to survive. The impacts are numerous and widespread."

The preliminary estimates indicate three multi-county areas appear to be the hardest hit. The area including Sutton, Crockett, western Kimble and eastern Pecos counties saw extensive mortality among Ashe junipers.

The area including Harris, Montgomery, Grimes, Madison and Leon counties saw extensive mortality among loblolly pines. Western Bastrop and eastern Caldwell counties, as well as surrounding areas, saw extensive mortality among cedars and post oaks.

Additionally, localized pockets of heavy mortality were reported for many other areas.

Texas Forest Service foresters plan to use aerial imagery to conduct a more in-depth analysis in the spring, which is when trees that may have gone into early dormancy - an act of self-preservation - could begin to make a comeback.

A more scientific, long-term study will be completed as the agency collects data through its FIA program. Considered a census for trees, the federally-funded program allows the agency to keep a close watch on trees - and how they're growing and changing - across the state.

As part of the program, foresters are tasked with surveying certain, designated plots of land each year. Because the state is so big, it takes a decade to complete a full inventory cycle.

"Quantifying the impacts of a statewide drought on tree survival is no small task," Carraway said, noting that Texas was home to 63 million acres of forestland, much of which is in remote areas.

"During this time of year, it's difficult to tell in some cases if a tree is truly dead. And keep in mind that the drought is ongoing. We fully expect mortality percentages to increase if the drought continues."